1. Field of the Invention
The present invention relates to a data migration management apparatus and an information processing system.
2. Description of the Related Art
The amount of data being handled by companies is increasing every year. For this reason, companies are using a plurality of different storage controllers to construct relatively large-scale information processing systems that manage large volumes of data. Since the frequency with which data is utilized will decrease in accordance with the passage of time, the location where data is stored is reallocated in accordance with the data utilization frequency.
Accordingly, the effective use of the storage resources inside a data processing system is accomplished by storing data that has a relatively high utilization frequency in a faster logical volume, and migrating data that has a relatively low utilization frequency to a slower logical volume. In the prior art, migration-targeted data is reallocated within the information processing system by copying backup data to the migration-destination logical volume.
However, in a method that makes use of backup data, the host computer is prohibited from accessing the migration-targeted data until data reallocation has ended. Therefore, the processing of work on the host computer must stop until data reallocation is over, lowering usability. Accordingly, technology that enables the reallocation of data without suspending host computer access has been proposed (U.S. Pat. No. 5,680,640).
In a case where data is migrated while the host computer is permitted access as in the prior art disclosed in the above-mentioned patent document, host computer access to data and a data copy for migrating this data are generated simultaneously. This increases the I/O (Input/Output) load of the migration-targeted data.
If host computer access frequency is high in this case, the processing load of the storage controller increases, lengthening the time required for a data copy to be completed. Not only that, but when processing is carried out giving priority to host computer access, there is also the possibility of a data copy process ending in error as a result of a timeout error.
When a data migration ends in error, the user managing the information processing system must first specify which data migration, from among the plurality of data migrations that were set, has ended in error, and reset a new data migration.
In a relatively large-scale information processing system being used at a company or the like, a plurality of data may be reallocated at one time at this point. In addition, in a case where a plurality of different data are mutually associated, these mutually associated data must be migrated simultaneously.
In a relatively large-scale information processing system like this, a complicated data migration is planned and executed in the middle of the night when access is relatively scarce. If the planned data migration is not completed due to a partial error, the user must once again devise and reset a complicated data migration plan, lowering usability.
Furthermore, the new data migration plan should be reset in accordance with the reason for the failure of the initial data migration plan, but since the user resets the data migration plan relying on his experience and intuition, there is no guarantee that the new data migration will be completed as planned.